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Elucidation of ABO blood group gene expression though chromatin remodeling

通过染色质重塑阐明 ABO 血型基因表达

基本信息

批准号：
22390140
负责人：
KOMINATO Yoshihiko
金额：
$ 10.57万
依托单位：
Gunma University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2010
资助国家：
日本
起止时间：
2010 至 2012
项目状态：
已结题

项目摘要

The ABO blood group is of great importance in blood transfusion and personal identification. However, the mechanisms regulating human ABO gene expression remain obscure. On the basis of DNase I hypersensitive sites in and upstream of ABO in the human erythroleukemia cell line K562 in publicly available expression data from the UCSC Genome Browser (http://genome.ucsc.edu), we prepared reporter plasmid constructs including these sites. Subsequent luciferase assays indicated a novel positive regulatory element in intron 1. This element was shown to enhance ABO promoter activity in an erythroid cell-specific manner. Electrophoretic mobility shift assays demonstrated that it bound to the tissue-restricted transcription factor GATA-1 and GATA-2. Mutation of the GATA motifs to abrogate binding of this factor reduced the regulatory activity of the element. Thus, GATA transcription factors seem to be involved in the cell-specific activity of the element. Furthermore, we found that Bm phenotypes were associated with a partial deletion in intron 1 involving the element as well as a single point mutation of GATA site leading to reduced activity of the element. Therefore, it is plausible that deletion or a single point mutation of the erythroid cell-specific regulatory element could down-regulate transcription in the B^m allele, leading to reduction of B antigen expression in cells of erythroid lineage, but not in mucus-secreting cells. These results support the contention that the enhancer-like element in intron 1 of ABO has a significant function in erythroid cells.

ABO血型在输血和个人识别中具有重要意义。然而，调节人类ABO基因表达的机制仍不清楚。根据UCSC基因组浏览器（http：//www.example.com）公开提供的表达数据中人类红白血病细胞系K562中ABO及其上游的DNase I超敏位点，我们制备了包含这些位点的报告基因质粒构建体。genome.ucsc.edu随后的荧光素酶分析表明，在内含子1的一个新的正调控元件。该元件显示以红系细胞特异性方式增强ABO启动子活性。电泳迁移率变动分析表明，它结合到组织限制性转录因子加塔-1和加塔-2。突变的加塔基序，废除该因子的结合降低了该元素的调节活性。因此，加塔转录因子似乎参与了该元件的细胞特异性活性。此外，我们发现Bm表型与内含子1中涉及该元件的部分缺失以及导致该元件活性降低的加塔位点的单点突变相关。因此，红系细胞特异性调控元件的缺失或单点突变可能下调B^m等位基因的转录，导致红系细胞中B抗原表达的减少，但在粘液分泌细胞中则不然。这些结果支持ABO内含子1中的增强子样元件在红系细胞中具有重要功能的论点。